The type of product does not limit the embodiments in accordance with the present invention. The following background art is an example of a product in which one embodiment, in accordance with the present invention, can be applied. One skilled in the art will recognize the multitude of products to which the embodiments of the present invention can be applied.
Direct access storage devices (DASD) have become part of every day life, and as such, expectations and demands continually increase for greater speed for manipulating data and for holding larger amounts of data. To meet these demands for increased performance, the mechanical assembly in a DASD device, specifically the Hard Disk Drive (HDD) has undergone many changes.
Shown in FIG. 1 is the relationship of components and sub-assemblies of HDD 110 and a representation of data tracks 136 recorded on disk surface 135. The cover is removed and not shown so that the inside of HDD 110 is visible. The components are assembled into base casting 113, which provides attachment and registration points for components and sub-assemblies. Data is recorded onto disk surface 135 in a pattern of concentric rings known as data tracks 136. Disk surface 135 is spun at fast revolutions by means of a motor-hub assembly 130. Data tracks 136 are recorded onto disk surface 135 by means of magnetic head 156, which typically resides at the end of slider 155. FIG. 1 being a plan view shows only one head and one disk surface combination. One skilled in the art understands that what is described for one head-disk combination applies to multiple head-disk combinations. The embodiment in accordance with the present invention is independent of number of head-disk combinations. Slider 155 and consequently head 156 are incorporated into head gimbal assembly (HGA) 150. HGA 150 is incorporated into actuator 140, which is comprised of at least one arm 146, pivot bearing 145, and voice coil 143. Arm 146 supports HGA 150 over disk surface 135. Pivot bearing 145 allows for smooth and precise rotation of actuator 140. Actuator 140 precisely moves HGA 150 over disk surface 135 by means of electro-motive force (emf) produced between voice coil 143 and magnets 125. Emf is a force that is produced when a current is passed through voice coil 143 and is in close proximity to magnets 125. Only bottom magnet 125 is shown. Top and bottom magnets 125 are joined as pole piece assembly 120. Pole piece assembly 120 in conjunction with voice coil 143 constitutes a voice coil motor (VCM). The VCM positions head 156 via actuator 140 by producing a controlled emf. Current is passed through voice coil 143 from controller 117. The required amount of current from controller 117, to produce the desired amount of emf, is determined by location information (stored in other electronic components not shown in FIG. 1) for data tracks 136 and location information stored in data tracks 136. Electronic commands for accessing data tracks 136 pass from controller 117 through flex cable 118 and into voice coil 143. Small corrections to the position of head 156 are determined from retrieved information from data tracks 136. This retrieved information is sent back to controller 117 so that small corrections can be made to the location and the appropriate current can be sent from controller 117 to voice coil 143. Once the desired data track is located, data is either retrieved or manipulated by means of electronic signals that pass through connector 111 and through flex cable 118. Connector 111 is the electronic interface that allows data to be transferred in and out of HDD 110.
The above cited art is exemplary of a product with components and process steps that must be coordinated into a build schedule to produce a final product. The given example of an HDD, in no way limits the embodiment, in accordance with the present invention, from being applied to any product requiring a product build schedule. One of the challenges for determining a product build schedule is the coordination of the fabrication, delivery, and assembly of the many components involved so that a final product can be produced in a timely and effective manner. Challenges become greater when a prototype part or process is introduced as a change to the final product. The scheduling of vendors, parts and support personnel to effectively produce the final product becomes a large challenge. Engineering judgment, which has been used in the past for estimating a build schedule for producing a final part, does not accurately predict the arrival time of a product in a manufacturing environment.